JP2008298485A - Photoelectric sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small, highly reliable photoelectric sensor having built therein a multi-layer substrate superior in mounting density. <P>SOLUTION: This photoelectric sensor 1 comprises a multi-layer substrate 100 having optical elements 111, 131 and a multi-purpose IC mounted on an identical face. A common recessed section 130 in which the optical element 111 and the multi-purpose IC are accommodated is formed on the identical face of the multi-layer substrate 100, and recessed sections 140, 150 are formed at a part of the bottom face of the common recessed section. The multi-purpose ICs are accommodated in the recessed sections 140, 150, respectively, and the optical element 131 is placed on the bottom face 130a out of the recessed sections 140, 150 in the common recessed section 130. The whole top face of each of the multi-purpose ICs is covered with a light-shading resin. A light transmissive resin is injected to the common recessed section so as to cover at least the top face of the optical element 131. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a photoelectric sensor used for optically detecting the presence or absence of an object.

Conventionally, a photoelectric sensor has been used to optically detect the presence or absence of an object. In order to reduce the size of the photoelectric sensor, a so-called multilayer structure in which a large number of active elements and passive elements are mounted on a single substrate inside the photoelectric sensor, and circuit patterns are three-dimensionally formed on the stacked substrates. A multilayer substrate may be used (for example, refer to Patent Document 1).
JP-A-6-42983 (page 5, FIG. 1)

  For example, a light emitting element, a light receiving element, a display LED, and a general-purpose IC having a function of detecting the presence or absence of an object by controlling these elements are mounted on the multilayer substrate built in the photoelectric sensor. Optical elements such as a light projecting element, a light receiving element, and a display LED are respectively housed in recesses formed on one side surface of the multilayer substrate so as not to interfere with each other. Are optically isolated. Also, these optical elements are wire-bonded to the circuit pattern of the multilayer substrate, and are connected to these optical elements and the LED so that the light projecting element and the light receiving element can function with each other and the display LED can be recognized from the outside. The bonding wire is covered with, for example, a transparent epoxy resin.

  On the other hand, general-purpose ICs other than these elements are often based on silicon, for example, and may cause malfunctions in response to light. Therefore, the upper surface of the multilayer substrate is independent of the above-described optical elements. A recess portion is provided in the recess portion, accommodated in the recess portion, wire-bonded to the circuit pattern of the multilayer substrate, and then covered with, for example, a light-blocking epoxy resin that does not transmit light.

  However, if the multilayer substrate has such a configuration, in addition to the recesses for accommodating each optical element, it is necessary to separately provide the recesses for accommodating general-purpose ICs. As a result, the entire photoelectric sensor incorporating the same is also enlarged.

  An object of the present invention is to provide a small and highly reliable photoelectric sensor provided with a multilayer substrate having a high mounting density.

In order to solve the above-described problems, the photoelectric sensor according to the present invention is:
A photoelectric sensor including a multilayer substrate in which an optical element and a general-purpose IC are mounted on the same side,
On the same side surface of the multi-layer substrate, a common dent portion that accommodates both the optical element and the general-purpose IC is formed, and a further dent portion is formed on a part of the bottom surface of the common dent portion,
The general-purpose IC is accommodated in the further recessed portion, and the optical element is disposed on the bottom surface of the common recessed portion other than the further recessed portion,
The entire upper surface of the general-purpose IC is covered with a light-shielding resin, and the common recess is filled with a light-transmitting resin so as to cover at least the upper surface of the optical element.

  The photoelectric sensor according to the present invention includes the multilayer substrate having such a structure, so that a two-stage configuration is provided in which a further concave portion for accommodating a general-purpose IC is provided on the bottom surface of the common concave portion. The general-purpose IC is not adversely affected by light by covering the entire upper surface of the general-purpose IC with a light-shielding resin. In addition, since the optical element is disposed at the bottom of the common concave portion above the housing portion of the general-purpose IC and the upper surface of the optical element is entirely covered with a transparent resin, the function of the optical element is impaired. There is no.

  In this way, the optical element having the function of emitting and receiving light and the general-purpose IC that should not be adversely affected by the light are accommodated in a common recess, thereby allowing the multilayer substrate to There is no need to provide a recess for accommodating a general-purpose IC separately from the optical element, and the entire multilayer substrate can be reduced in size, and thus the photoelectric sensor can be reduced in size.

Moreover, the photoelectric sensor according to claim 2 of the present invention is the photoelectric sensor according to claim 1,
The optical element comprises any one of a light projecting element, a light receiving element, and a display LED.

  Even if the optical element provided on the same side of the multilayer substrate is any one of a light projecting element, a light receiving element, and a display LED, the optical element accommodating recess and the general purpose are provided on the same side of the multilayer substrate. Since there is no need to separately form the IC accommodating recess, it is possible to achieve a reduction in the size of the entire multilayer board, which has been difficult to achieve in the past, and a reduction in the size of the photoelectric sensor.

Moreover, the photoelectric sensor according to claim 3 of the present invention is the photoelectric sensor according to claim 1,
The optical element includes at least two of a light projecting element, a light receiving element, and a display LED, and one of the optical elements and the general-purpose IC are housed together in the common recess, and the other light The elements are respectively housed in recesses formed individually on the same surface of the multilayer substrate, and the upper surfaces of the other optical elements are covered with a light-transmitting resin.

  The photoelectric sensor according to the present invention includes the multilayer substrate having such a structure, so that at least two of the light projecting element, the light receiving element, and the display LED are individually formed on the same side surface of the multilayer substrate. As a result, each optical element is optically isolated, and any one of the optical elements and the general-purpose IC are accommodated in one common recess, thereby integrating the entire multilayer substrate. Can be reduced in size, and as a result, a highly reliable small photoelectric sensor can be obtained.

  According to the present invention, it is possible to provide a small and highly reliable photoelectric sensor provided with a multilayer substrate having a high mounting density.

  Hereinafter, a photoelectric sensor 1 according to an embodiment of the present invention will be described. As shown in FIG. 1, the photoelectric sensor 1 according to an embodiment of the present invention is provided in two halved cases 10 (11, 12) that are fitted to each other to form a rectangular parallelepiped shape, and on the front surface of the case 10. The lens unit 20, a multilayer substrate 100 disposed on the back surface of the lens unit 20, a cable 30 led out of the case and electrically connected to the multilayer substrate 100, and a plug 15 covering a part of the case 10. ing. The case 10 is made of a material having excellent strength and moldability, such as ABS resin (acrylonitrile, butadiene, styrene resin), and is formed into a rectangular parallelepiped shape by being integrated with each other with screws (not shown).

  The lens unit 20 includes a light projecting lens 21 and a light receiving lens 22, and detects light from the light projecting element 111 provided in the multilayer substrate 100 shown in FIG. 2 via the light projecting lens 21 to the outside of the photoelectric sensor 1. In addition to projecting light, when the detection light projected from the light projecting element 111 is reflected back through the object, it is received by the light receiving element 131 of the multilayer substrate 100 via the light receiving lens 22 of the lens unit 20. It has become.

  In the case of this embodiment, the multilayer substrate 100 has a multilayer structure in which, for example, layers made of thin ceramics are stacked as shown in FIG. 3, and the light projecting element is accommodated on one side surface 100a thereof as shown in FIG. The recessed portion 110 for receiving, the recessed portion 120 for accommodating the display LED, and the other recessed portion 130 for housing the other light receiving elements 131 and the general-purpose ICs 141 and 151 to 153 are formed independently (by optical isolation). ing.

  The multilayer substrate 100 described above may have a multilayer structure of a printed board made of glass epoxy resin instead of the multilayer structure of a ceramic substrate.

  In addition, a circuit pattern (not shown) is formed at appropriate positions on each layer of the multilayer substrate 100, and a three-dimensional circuit pattern is formed inside the multilayer substrate via via holes (not shown) such as through holes and inner via holes. Yes. In addition, on one side surface 100a of the multilayer substrate 100, three terminals 101, 102, 103 are formed in the vicinity of the edge on the light projecting element side, and are electrically connected to the cable 30 described above. In addition, positioning holes 105 and 106 are formed in the vicinity of the terminal 103 and on the opposite side of the one side surface 100a of the multilayer substrate 100 in the diagonal direction, and the multilayer substrate 100 is attached to the lens unit 20 via the positioning holes 105 and 106. It is fixed while maintaining an optically appropriate relative positional relationship.

  On the other hand, a circuit pattern not shown in detail here is formed on the other side surface 100b (see FIG. 3) of the multilayer substrate 100, and a large number of passive elements (not shown) such as capacitors, resistors, and diodes are provided at appropriate positions of each circuit pattern. ) Is mounted by surface mounting technology (SMT). Also, a sensitivity adjustment volume 109 is mounted on one terminal of the other side surface 100b (see FIG. 1).

  As shown in FIG. 3, the light projecting element 111 is disposed on the bottom surface of the light projecting element housing recess 110, and is electrically connected to an appropriate position of the circuit pattern of the multilayer substrate 100 by a bonding wire 112. The light projecting element 111 and the bonding wire 112 are filled in the light projecting element housing recess 110 with a resin part 113 made of, for example, a transparent epoxy resin having excellent translucency. In addition, the display LED accommodating recess 120 is formed in the vicinity of the end of the multilayer substrate 100 opposite to the light projecting element accommodating recess 110 as described above, and the display LED 121 is formed on the bottom surface of the recess 120. The LED 121 for display and a circuit pattern (not shown) are electrically connected by the bonding wire 122 while being disposed. In addition, in the display LED housing recess 120, a resin portion 123 made of, for example, a transparent epoxy resin having excellent translucency so as to cover the display LED 121 and the bonding wire 122 is formed in the display LED housing recess 120. Filled.

  As shown in detail in FIGS. 2 and 4, the light receiving element 131 and the general-purpose ICs 141, 151-1 are disposed between the light projecting element housing recess 110 and the display LED housing recess 120 on one side surface 100 a of the multilayer substrate 100. A common recess 130 that accommodates 153 is formed. The common recess 130 is provided with further recesses 140 and 150 (see FIG. 2) on a part of the bottom surface thereof, and the bottom surface 130a (see FIG. 4) other than the further recess of the common recess 130 receives light. The element 131 is disposed and is electrically connected to the circuit pattern of the multilayer substrate 100 via bonding wires 132 (see FIG. 2). Further, the general-purpose IC 141 is disposed in the further recessed portion 140 formed in a part of the bottom surface 130 a of the common recessed portion 130, and is formed on the bottom surface of the common recessed portion 130 adjacent to the further recessed portion 140. The general-purpose ICs 151 to 153 are also arranged in the further recess 150. In the case of this embodiment, these general-purpose ICs include a first general-purpose IC 141 that is a custom IC for achieving the function of the photoelectric sensor 1 and second general-purpose ICs 151 to 153 on which transistors and diodes are mounted. These general-purpose ICs 141 and 151 to 153 are also electrically connected to the circuit pattern of the multilayer substrate 100 through bonding wires 144 and 154. And the circumference | surroundings and upper surface of general purpose IC141,151-153 accommodated in the further recessed parts 140 and 150, and the bonding wires 144 and 154 are covered with the black resin parts 145 and 155 which have light-shielding property ( FIG. 5 shows a state close to the actual appearance).

  In this case, in this embodiment, the black resin portion 145 uses a black epoxy resin containing a filler or an equivalent product.

  Note that the upper surfaces of the light-shielding resin portions 145 and 155 do not cover the upper surface (light-receiving surface) of the light-receiving element 131 arranged one step above the general-purpose IC 141, as shown in FIG. The light detection characteristics are not impaired. The common recess 130 includes the entire periphery including the upper surface of the light receiving element 131, the above-described general-purpose ICs 141, 151 to 153, the bonding wires 144 and 154 connected to the light receiving element 131, and the light-shielding black resin portion 145. , 155 is filled with, for example, a transparent epoxy resin 135 having translucency. That is, it has a two-layer structure in which a light-transmitting resin portion 135 is laminated on an upper layer of the light-blocking resin portion 145.

  The resin portion 135 is filled up to the upper surface of the common recess portion 130, but does not necessarily need to be flush with the upper surface. It is sufficient if the resin portion 135 is filled to cover the above-described components. is there. Moreover, it may be filled beyond the upper surface.

  The multilayer substrate 100 of the photoelectric sensor 1 according to the above-described embodiment of the present invention has such a structure, that is, a two-stage configuration in which further concave portions 140 and 150 for accommodating general-purpose ICs are provided on the bottom surface of the common concave portion 130. In addition, the general-purpose ICs 141 and 151 to 153 are disposed in the further recessed portions 140 and 150, respectively, and the general-purpose ICs 141 and 151 to 153 are covered with a light-shielding black resin, for example, so that the general-purpose ICs 141 and 151 to 153 are adversely affected by light. You will not receive it. In addition, a light receiving element 131 is arranged on the bottom surface 130a of the common recessed portion 130 located above the further recessed portions 140 and 150 for accommodating the general-purpose IC, and the light receiving element 131 and the bonding wire 132 connected thereto are provided. Is entirely covered with the resin portion 135 made of a translucent transparent resin, including the upper surface of the black resin portion 145, so that the light receiving element 131 is not prevented from receiving light.

  Further, according to the photoelectric sensor 1 of the present invention, the light receiving element 131 that needs to react to light and the general-purpose ICs 141 and 151 to 153 that should not react to light are housed together in the same housing portion. Therefore, it is possible to contribute to the integration of the multilayer substrate 100 accommodated in the photoelectric sensor 1, to reduce the size of the multilayer substrate 100, and to achieve the size reduction of the photoelectric sensor 1.

  In addition, the light projecting element 111, the light receiving element 131, and the display LED 121, which are optical elements in the present embodiment, are accommodated in the respective recessed portions 110, 130, and 120 individually formed on the same side surface of the multilayer substrate 100. Therefore, they are optically isolated and do not interfere with each other. Therefore, the reliability of the photoelectric sensor according to this embodiment can be improved.

  In addition, the bonding wire of the general-purpose IC in the above-described embodiment may be covered with a light-shielding resin that covers the upper surface of the general-purpose IC, or may be covered with a light-transmitting resin in an upper layer.

  Further, the light-shielding resin is not limited to the black resin as in the above-described embodiment, and various resins such as a brown resin can be used as long as they have substantially light-shielding properties.

  In the above-described embodiment, the light projecting element, the light receiving element, and the display LED are exemplified as the optical element. However, it goes without saying that other optical elements are also applicable to the present invention.

  In addition, the general-purpose IC and the light receiving element are not housed in the above-described common recess as in the above-described embodiment, but the general-purpose IC and another optical element (either the light projecting element or the display LED) are commonly recessed. You may accommodate in a part. Also in this case, each remaining optical element is housed in a separate housing recess and is optically isolated, thereby increasing the integration density of the multilayer substrate, reducing the size, and reducing each light similarly to the above-described embodiment. There is no interference between the elements, and the photoelectric sensor can be small and highly reliable.

  Unlike the above-described embodiment, the optical element provided in the multilayer substrate is composed of any two of a light projecting element, a light receiving element, and a display LED, and any one of these optical elements is shared with a general-purpose IC. The optical elements are accommodated together in the recesses, and the other optical elements are accommodated in the recesses individually formed on the same side surface of the multilayer substrate, and the upper surfaces of the other optical elements are covered with a light-transmitting resin. Even if it is known, the effects of the present invention can naturally be exhibited.

  Further, even if the optical element provided on the same side surface of the multilayer substrate is only one of the light projecting device, the light receiving device, and the display LED, the light is applied to the same side surface of the multilayer substrate as in the prior art. Since there is no need to separately form the element housing recess and the general-purpose IC housing recess, the multilayer substrate can be reduced in size and the effects of the present invention can be exhibited.

It is a disassembled perspective view of the photoelectric sensor which concerns on one Embodiment of this invention. It is a top view of the multilayer substrate of the photoelectric sensor shown in FIG. FIG. 3 is a side sectional view of the multilayer substrate shown in FIG. 2. FIG. 4 is a detailed cross-sectional view showing an enlarged common recess portion of the cross-sectional view shown in FIG. 3. It is the top view which showed the top view shown in FIG. 2 according to the actual aspect.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Photoelectric sensor 10 (11, 12) Case 15 Plug 20 Lens unit 21 Emitting lens 22 Light receiving lens 30 Cable 100 Multilayer substrate 100a One side surface 100b Other side surface 101,102,103 Terminal 105,106 Positioning hole 109 Sensitivity adjustment volume 110 Light Emitting Element Receiving Recess 111 Light Emitting Element 112 Bonding Wire 113 Resin Part 120 Display LED Receiving Recess 121 Display LED
122 Bonding wire 123 Resin portion 130 Common recess portion 130a Bottom surface 131 Light receiving element 132 Bonding wire 135 Resin portion 140 Further recess portion 141 General-purpose IC
144 Bonding wire 145 Resin part 150 Further recessed part 151-153 General purpose IC
154 Bonding wire 155 Resin part

Claims (3)

A photoelectric sensor including a multilayer substrate in which an optical element and a general-purpose IC are mounted on the same side,
On the same side surface of the multi-layer substrate, a common dent portion that accommodates both the optical element and the general-purpose IC is formed, and a further dent portion is formed on a part of the bottom surface of the common dent portion,
The general-purpose IC is accommodated in the further recessed portion, and the optical element is disposed on the bottom surface of the common recessed portion other than the further recessed portion,
The entire upper surface of the general-purpose IC is covered with a light-shielding resin, and the common recess is filled with a light-transmitting resin so as to cover at least the upper surface of the optical element. .   The photoelectric sensor according to claim 1, wherein the optical element is one of a light projecting element, a light receiving element, and a display LED. The optical element includes at least two of a light projecting element, a light receiving element, and a display LED, and one of the optical elements and the general-purpose IC are housed together in the common recess, and the other light The elements are respectively housed in recesses formed individually on the same surface of the multilayer substrate, and the upper surfaces of the other optical elements are covered with a light-transmitting resin. Item 2. The photoelectric sensor according to Item 1.

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